Frequently Asked Questions
Licensing, migration from PrimeNG, the ecosystem, and how support works.
The Project #
Is Optimus UI free? Will it stay free?
Yes, and yes. Every package is MIT licensed, and the code we forked was MIT too, so relicensing it is not something we could do even if we wanted to. There is no paid tier and none is planned. The philosophy page goes into what that does and does not buy you.
Is this an official PrimeNG fork? Are you affiliated with PrimeTek?
No. Optimus UI is an independent community fork, not affiliated with, endorsed by, or sponsored by PrimeTek. It is a separate repository seeded with PrimeNG's MIT licensed code and history, not a fork of the archived primefaces/primeng repository.
Which PrimeNG version is this forked from?
PrimeNG v21, the last version published under the MIT license. Optimus UI v1 is that codebase, rebranded, with the fixes that have landed since.
Who maintains it, and how is it funded?
A small group of volunteers, with OpenNG covering hosting and the domain. We are deliberate about not implying more than that — see sustainability for the honest version and the ways that can change.
Why did the name change?
Trademark. PrimeNG, PrimeFaces and PrimeFlex are PrimeTek's marks, so the packages, the CSS cascade layer and the icon library all needed new names. That is also why the rename is handled by a schematic rather than by asking you to rewrite imports by hand.
Compatibility & Migration #
Which Angular versions are supported?
Angular v21 and newer. Our majors follow Angular's — when a new Angular major ships, a compatible Optimus UI major is the first thing we work on.
How do I migrate from PrimeNG? Is it automatic?
Mostly. Run ng add @openng/optimus-ui in a PrimeNG v21 workspace and it detects the existing dependency and runs the full migration: packages swapped, imports rewritten, dependencies installed. It then prints a report of anything it could not rewrite, with file and line numbers. The migration guide covers the details and the manual cases.
I am on PrimeNG v20 or older. Can I migrate directly?
No. Upgrade to PrimeNG v21 first, using PrimeNG's own migration guides, then run the schematic. The schematic checks the version and refuses rather than producing a half-migrated workspace.
What happens to my PrimeNG license?
Nothing — it is unrelated. A PrimeNG v22 commercial license covers PrimeNG. Optimus UI needs no license at all. If you hold a PrimeTek subscription for their templates or theme designer, those remain their products and do not carry over here.
I had an open PR on primefaces/primeng. Can I bring it here?
Yes, and we would like you to. Append .patch to your original pull request URL and apply it with git am — the contributing guide in the repository walks through it, including what to do when the patch no longer applies cleanly.
Can I run PrimeNG and Optimus UI side by side?
Technically yes, since the package names and the CSS cascade layer differ, but you will ship two copies of the same components and two theme runtimes. Treat it as a temporary state during migration rather than a supported configuration.
Themes, Icons & Ecosystem #
Do the PrimeNG themes work?
The built-in presets do — Aura, Material, Lara and Nora ship in @openng/optimus-ui-themes and are configured the same way. A preset you wrote yourself against PrimeNG v21 will work after the import paths are updated, which the migration schematic handles.
What about the Theme Designer, templates and blocks?
Those are PrimeTek's commercial products. They were never MIT licensed, so they are not part of this fork and we will not be reimplementing them. Theming in Optimus UI means editing preset objects in code, which is documented in full under styled mode.
What replaced PrimeIcons?
OpenNG Icons, installed as @openng/icons. The pi pi-{icon} class names are unchanged, so templates do not need editing — only the package name and the stylesheet import, both of which the migration schematic rewrites.
What about PrimeFlex?
PrimeFlex is not maintained here. We suggest Tailwind CSS instead, and ship @openng/optimus-ui-tailwindcss for first-class integration — see the Tailwind guide. The PrimeFlex guide covers moving across.
Does Optimus UI work with SSR?
This documentation site is itself an Angular SSR application built on Optimus UI, prerendered at build time. So yes, and any regression there tends to be noticed quickly.
Support & Contributing #
Is there commercial support?
No. There is no SLA, no support contract and no guaranteed response time. Issues and discussions are answered by volunteers when they have time. If your organisation needs contractual guarantees, this project cannot offer them.
How do I report a bug?
Open an issue on GitHub with a minimal reproduction — a StackBlitz from any demo on this site is ideal — plus your Optimus UI, Angular and browser versions. A reproduction is the difference between a bug that gets fixed and one that sits in the backlog.
How do I request a feature?
Open a discussion. Requests are triaged and welcome, but in practice they ship when someone implements them. If it matters to you, the contribution guide is the fastest route.
Where do I ask questions?
GitHub Discussions is the primary place. There is also an Ask AI button in the header, which answers from this documentation. Optimus UI does not run its own Discord — the Discord links here point to the general Angular community server.
How does versioning work?
Semantic versioning, with majors tracking Angular majors. Breaking changes are confined to majors and documented in the changelog.